Field of the Invention
The present invention relates to a device for preventing the scattering of molded articles ejected from a resin molding machine which produces a plastic, and, more particularly, to a device for screening the vicinity of a mold so as to prevent the scattering of molded articles when ejected from the mold immediately after they have been processed by an injection molding machine.
Description of the Prior Art
Known and commonly used injection molding machines comprise a frame 21, an injection mechanism section 22, a mold clamping mechanism section 23, a hydraulic drive section 24, an electric control section, and so on, as shown in FIGS. 17 and 18.
The injection mechanism section 22 is generally designed to inject a melting material through a main sprue (not shown) into a runner which communicates with a plurality of cavities through gates.
The mold clamping mechanism section 23 includes a fixed die plate 26, a movable die plate 27, tie bars 28 (28.sub.1 to 28.sub.4) inserted through the fixed and movable die plates 26 and 27 at the four corners thereof, a fixed mold 29 mounted on the fixed die plate 26, and a movable mold 30 mounted on the movable die plate 27. When the molds are opened after the molding has been completed, an ejector 31 drops molded articles into a discharge section 32 where the molded articles are accommodated in a certain container.
In the case of resin molded articles of the type which need to be kept clean, attention must be paid to ensure that not even one soiled molded article is included so as to avoid the problems which might otherwise occur when they are assembled to form a finished product.
However, in the conventional injection molding machine, since both sides of the opened molds 29 and 30 fixed to the fixed and movable die plates 26 and 27 are open, when the molded articles are released from the mold by the ejector 31, the runner and the molded articles are separated from each other at the connecting gates and the separated molded articles are often struck against the lower tie bars and are soiled by a lubricant for the movable die plate or fall on the base surface of the frame and are dirtied by the oil coated thereon. Alternatively, the molded articles do not drop into the container but are scattered therearound.
If the molded parts are of the type which need to be kept clean, inclusion of even one that is soiled may lead to an accident or failure during assembly.
Even if the number of molded articles accommodated in the container is counted by a counter, a tendency for some to scatter around the container makes a precise count impossible, and may lead to a shortage of parts during assembly.
Accordingly attempts have been made to provide a barrier around the exterior of the mold of the injection molding machine so as to prevent the released, molded articles from scattering and being soiled.
Such a scattering prevention screen has been proposed in the specifications of, for example, Japanese Utility Model Laid-Open No. 159225/1981 (which corresponds to Japanese Utility Model Application No. 58996/1980 entitled Movable Curtain for Plastic Molding Machine) and Japanese Utility Model Laid-Open No. 194011/1983 (which corresponds to Japanese Utility Model Application No. 92043/1982 entitled Guide Skirt for Plastic Molding Machine). In both cases, the screening device is fixed by inserting bolts or vices into threaded holes in the molds or die plates. However, drilling of the threaded holes in the molds or die plates is a time-consuming task and requires skill. When the screening device is shifted, more threaded holes must be drilled at new positions, making the mounting of the screening device even more troublesome. Further, the molds have to be inspected or maintained frequently, and the stationary screening device must therefore be removed and mounted each time such inspection or maintenance takes place. This is time-consuming and may cause problems in terms of production efficiency and safety.